1. Field of the Invention
The present invention relates to a coin selector and selection method for coin-operated machines for detecting fraud in coin insertion. More particularly, the present invention relates to a coin selector applied to a coin-operated machine such as a gaming machine, and relates also to an error detecting method to detect fraud in coin insertion through the same selector.
2. Description of the Prior Art
A coin-operated machine is operated in response to insertion of coins, tokens, medals or other disks (herein referred to as coins) into a coin inlet or passageway. Such coin-operated machines include slot machines, other gaming machines, vending machines and money-changing machines. In a slot machine for example, an acceptable coin must be selected before a game can begin, in order to prevent the machine from operating by insertion of a slug or unacceptable coin different from the genuine acceptable coin of a predetermined denomination.
To automate the selection of acceptable coins for the slot machine, there has been proposed a coin selector as illustrated in FIG. 6. In this conventional coin selector, a coin 9 is sensed through an inlet slot of the slot machine and passed along a coin passageway 10, which communicates both with an accepting chute 11 and a return chute 12. The coin 9 is detected twice: by a magnetic sensor 13 and by a photo sensor 14. A gate 15 is swingable between a position wherein the coin 9 from the passageway 10 is passed to the accepting chute 11, shown in phantom line in FIG. 6, and another position wherein the coin 9 is passed to the return chute 12 shown in full line in FIG. 6.
An inspection signal of the coin 9 is sent from the magnetic sensor 13 to a controller 16, and is evaluated as to whether it represents an acceptable or unacceptable coin. When the coin 9 is acceptable, the plate 15 is moved to the accepting position by actuation of a solenoid 17, so as to guide the acceptable coin 9 into the accepting chute 11. The acceptable coin 9 then passes the photo sensor 14 to cause it to output a detection signal to the controller 16, which evaluates the detection signal as to effectiveness. To conduct the latter evaluation, the controller 16 judges a time period T1 which begins with inspection signal and ends with the detection signal. When the detection signal is judged as effective, the controller 16 actuates a slot machine mechanism 18. The player can play games corresponding to the number of coins inserters.
The conventional coin selector, however, suffers from the disadvantage of being vulnerable to fraud by use of a tool as illustrated in FIG. 7, enabling a player to play games without paying coins. A celluloid plate 19 of the tool is crooked in correspondence with the inside of the passageway 10, and is provided with three slots 19a to 19c in positions corresponding to the downstream sensor 14. An acceptable coin 9 as a decoy is secured to the celluloid plate 19 in the position corresponding to the upstream sensor 13. The coin 9 is evaluated as acceptable by the sensor 13 and the controller 16. The slots 19a to 19c are detected by the photo sensor 14, and cause the controller 16 to generate three detection signals before the lapse of time T1 from the sensing of the coin 9 by the sensor 13, and are evaluated as effective three times. One use of the celluloid plate 19 thus enables the user to play three games without actually paying any coins.